The patch titled
Subject: watchdog/perf: add a weak function for an arch to detect if perf can use NMIs
has been added to the -mm mm-nonmm-unstable branch. Its filename is
watchdog-perf-add-a-weak-function-for-an-arch-to-detect-if-perf-can-use-nmis.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/watchdog-perf-add-a-weak-function-for-an-arch-to-detect-if-perf-can-use-nmis.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Douglas Anderson <dianders@xxxxxxxxxxxx>
Subject: watchdog/perf: add a weak function for an arch to detect if perf can use NMIs
Date: Fri, 19 May 2023 10:18:39 -0700
On arm64, NMI support needs to be detected at runtime. Add a weak
function to the perf hardlockup detector so that an architecture can
implement it to detect whether NMIs are available.
Link: https://lkml.kernel.org/r/20230519101840.v5.15.Ic55cb6f90ef5967d8aaa2b503a4e67c753f64d3a@changeid
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Chen-Yu Tsai <wens@xxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Colin Cross <ccross@xxxxxxxxxxx>
Cc: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Guenter Roeck <groeck@xxxxxxxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Lecopzer Chen <lecopzer.chen@xxxxxxxxxxxx>
Cc: Marc Zyngier <maz@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Masayoshi Mizuma <msys.mizuma@xxxxxxxxx>
Cc: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Petr Mladek <pmladek@xxxxxxxx>
Cc: Pingfan Liu <kernelfans@xxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: "Ravi V. Shankar" <ravi.v.shankar@xxxxxxxxx>
Cc: Ricardo Neri <ricardo.neri@xxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Stephen Boyd <swboyd@xxxxxxxxxxxx>
Cc: Sumit Garg <sumit.garg@xxxxxxxxxx>
Cc: Tzung-Bi Shih <tzungbi@xxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/nmi.h | 1 +
kernel/watchdog_perf.c | 12 +++++++++++-
2 files changed, 12 insertions(+), 1 deletion(-)
--- a/include/linux/nmi.h~watchdog-perf-add-a-weak-function-for-an-arch-to-detect-if-perf-can-use-nmis
+++ a/include/linux/nmi.h
@@ -210,6 +210,7 @@ static inline bool trigger_single_cpu_ba
#ifdef CONFIG_HARDLOCKUP_DETECTOR_PERF
u64 hw_nmi_get_sample_period(int watchdog_thresh);
+bool arch_perf_nmi_is_available(void);
#endif
#if defined(CONFIG_HARDLOCKUP_CHECK_TIMESTAMP) && \
--- a/kernel/watchdog_perf.c~watchdog-perf-add-a-weak-function-for-an-arch-to-detect-if-perf-can-use-nmis
+++ a/kernel/watchdog_perf.c
@@ -234,12 +234,22 @@ void __init hardlockup_detector_perf_res
}
}
+bool __weak __init arch_perf_nmi_is_available(void)
+{
+ return true;
+}
+
/**
* watchdog_hardlockup_probe - Probe whether NMI event is available at all
*/
int __init watchdog_hardlockup_probe(void)
{
- int ret = hardlockup_detector_event_create();
+ int ret;
+
+ if (!arch_perf_nmi_is_available())
+ return -ENODEV;
+
+ ret = hardlockup_detector_event_create();
if (ret) {
pr_info("Perf NMI watchdog permanently disabled\n");
_
Patches currently in -mm which might be from dianders@xxxxxxxxxxxx are
migrate_pages-avoid-blocking-for-io-in-migrate_sync_light.patch
watchdog-perf-define-dummy-watchdog_update_hrtimer_threshold-on-correct-config.patch
watchdog-perf-more-properly-prevent-false-positives-with-turbo-modes.patch
watchdog-hardlockup-add-comments-to-touch_nmi_watchdog.patch
watchdog-perf-rename-watchdog_hldc-to-watchdog_perfc.patch
watchdog-hardlockup-move-perf-hardlockup-checking-panic-to-common-watchdogc.patch
watchdog-hardlockup-style-changes-to-watchdog_hardlockup_check-is_hardlockup.patch
watchdog-hardlockup-add-a-cpu-param-to-watchdog_hardlockup_check.patch
watchdog-hardlockup-move-perf-hardlockup-watchdog-petting-to-watchdogc.patch
watchdog-hardlockup-rename-some-nmi-watchdog-constants-function.patch
watchdog-hardlockup-have-the-perf-hardlockup-use-__weak-functions-more-cleanly.patch
watchdog-hardlockup-detect-hard-lockups-using-secondary-buddy-cpus.patch
watchdog-perf-add-a-weak-function-for-an-arch-to-detect-if-perf-can-use-nmis.patch
arm64-enable-perf-events-based-hard-lockup-detector.patch
